Aquatic invasive species: The hitchhiking problem
Aquatic invasive species, like Eurasian watermilfoil, can attach themselves to boats and fishing equipment and move from one lake to another.
Friday, May 28, 2010 - 18:08
WEED EATER: A Eurasian watermilfoil weeding machine attempts to eradicate the invasion. (Photo: pawpaw67/Flickr)
Lake Champlain is filled with aquatic invasive species. Most estimates claim that the nearby St. Lawrence and Hudson rivers harbor about 90 invasive species each, and the also-nearby Great Lakes hold about two times that many. These are plants and animals that are not native to our local ecosystem — such as the zebra mussel, which most likely came from the Caspian Sea — and have the potential to cause economic and environmental damage to the area. Lake Champlain contains about 50 of these plants and animals, and the general consensus among scientists is that human activity is the primary means of their introduction into our ecosystem.
One problem with invasive species is that they can out-compete native plants and animals, which can limit biodiversity, disrupt the food chain and completely change our local ecosystem. Zebra mussels, for example, will attach to any hard surface — boats, docks, pipes, native clams and shipwrecks (and at right, a measurement device in Lake Michigan). Unfortunately many of the lake's 300 historic wooden shipwrecks are encrusted with zebra mussels, which could damage these national treasures.
Eurasian watermilfoil, another invasive native to Eurasia and Africa, grows in dense mats in shallow water blocking out light to native vegetation. These infestations can lower oxygen levels in the water and the resulting die-offs can increase nitrogen and phosphorus levels, which result in algal blooms. In general, the infestations are a nuisance to recreational lakegoers. Other notable invasive species in the lake include water chestnut, curly leaf pond weed and the ale wife.
Another major problem with these invasive plants and animals is that they are easily moved around from lake to lake by human activities. These invasives become aquatic hitchhikers, attaching themselves to boats, fishing gear and trailers. Eurasian watermilfoil can regenerate from a single plant fragment. Microscopic zebra mussel larvae can find their way into bilge water, live wells and bait buckets, and then be introduced into new water bodies. It is true that native animals have the ability to move these invasives around as well, but data seems to point to a more human culprit. Invasive species introductions and infestations usually first appear around popular boat launches and fishing areas. This trend applies to terrestrial invasive plants, as well, which tend to follow roadways.
Measures can be taken to stop the spread of aquatic invasive species. If you're a boater, inspect your boat for hitchhiking plants. Be sure to check the boat's trailer, license plate and wheel wells. Drain your bilge water and bait buckets to help prevent the spread of invasive species and aquatic diseases. If you have the time, wash your boat and let it dry for about five days — that is the ideal preventive measure and an excellent idea if you are moving your craft from one water body to another. We should all be concerned about new invasive species coming into our lakes, but we should also be cautious about what is coming out of the lake and moving to unaffected bodies of water.
Photo: Wikimedia Commons
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